Various systems utilize battery backup supply architectures, such as uninterruptible power supply (“UPS”) units. The UPS units include batteries that are charged during periods when the system is being powered by an external power supply. If the external power supply is lost, the batteries are used to power the system's load. A typical system may use two different power supplies, one to run the components (such as devices in a server array) and another to charge the batteries. This arrangement may also require that the system has separate charging and discharging circuits for the UPS units. These dual arrangements can be relatively costly to produce, set up, and power.
In some examples, charged UPS units may be removed from the external power supply and load and stored for a period of time. However, current may leak from the a battery during this storage period, causing the battery to be continuously discharged. As a result, the batteries of the UPS unit may be drained within a matter of months. If the battery charge becomes too low, the battery may not be able to be charged, and the UPS unit becomes unusable.